This report emerged in the course of the R&D project 'Evaluation of the CAP from a nature conservation point of view - increased efficiency through use of existing data sets', which was financed by the Federal Agency for Nature Conservation (Bundesamt für Naturschutz) with funds of the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety. The aim of this project was to investigate area-related impacts in terms of nature conservation due to the EU agricultural reform of 2003. The basis for quantitative analyses were data of the Integrated Administration and Control System (IACS), technical maps on protected areas and area related objectives for nature and water conservation, and site-specific information from four German federal states. Thus, the project served as well for developing methodologies for the analysis of IACS-data in connection with geo referenced technical data, and for collecting experiences with the evaluation of first pillar measures of the Common Agricultural Policy (CAP). A special focus was on the development of the grassland area. IACS-data provide highly disaggregated spatial information on the dynamic of agricultural land use. Regarding loss of grassland it could be shown that besides a conversion into arable land the 'de-activation' of grassland initially IACS-registered in 2005 played a role, because relevant areas were not registered in subsequent years. On basis of data for 2005 and 2007, conversion of grassland into arable use could be detected on more than 40,000 hectare, compared to 80.000 hectare grassland loss according to cross compliance statistics. The difference is due to 'de-activation'. However, the analyses detected conversion of grassland to arable land as well in ecologically sensitive areas, e.g. on organic soils. In addition existing support payments and mandatory rules from agricultural and environmental policy were examined with respect to possible protection effects for grassland. The report concludes with recommendations, particularly regarding the protection of grassland, a further development of the control system for landscape elements, and the usability of IACS-data.